Starting out: a sample project

[bbrtj]

If you'd like to give these libraries a try but don't have an idea what you can do with them, here's are some tasks you can complete without much Bitcoin knowledge:

Basic - key manipulation

1. Install Bitcoin::Crypto from CPAN. Generate a new wallet mnemonic phrase using generate_mnemonic from Bitcoin::Crypto::Util - this is the private master key, don't share it with anyone.
2. Import it as an extended private key using from_mnemonic from Bitcoin::Crypto::Key::ExtPrivate. Set the network of the key object to bitcoin_testnet using set_network.
3. By using derive_key_bip44 method, derive a key with a standard derivation path. Turn extended key into a regular private key (get_basic_key), private key into a public key (get_public_key), and public key into an address (get_address).
4. Generate a couple addresses this way, changing the derivation index of the master key. Try generating SegWit addresses using purpose => Bitcoin::Crypto::Constants::bip44_segwit_purpose. Verify whether you got it correct using tools like https://iancoleman.io/bip39/.

Advanced - transactions

1. Send your generated address to me. You can reach me in this thread or by mailing [email protected]. I will send some testnet coins to your address. Wait for the transactions to be confirmed on the blockchain. Use https://mempool.space/testnet to check your address.
2. Using mempool.space, get the raw transaction hex of the transaction I made. Import it into your program using extract method from Bitcoin::Crypto::Transaction::UTXO. You should be able to use get method from that class to obtain the UTXO object for the transaction.
3. Create and sign a transaction sending the testnet coins back to my address. Transaction support is documented in Bitcoin::Crypto::Manual::Transactions. There are also some transaction examples you can follow to make things easier. You should add at least one output to the transaction with the address which sent you the coins. Bonus points if you also add a NULLDATA output with text "Perl Rocks". You can keep some of the coins if you want to continue testing, by adding your own address as an output to the transaction.
4. Broadcast the signed transaction to the Bitcoin network. There are a couple of ways you can do this, but the easiest one is to use mempool.space again: https://mempool.space/testnet/tx/push.

Next steps

1. Tell us about your experience (using Discussions). Was it easy? Which part was the hardest?
2. Suggest improvements (using Issues or Discussions). Which part of the system seems unpolished or yields surprising results? Were there any bugs?
3. Give us your approval if we deserve it. Star us on GitHub and ++ us on MetaCPAN. Your informed endorsement will make the library more credible to others who may want to use it.
4. Stick around. Become an organization's member if you haven't already. Learn more about Bitcoin, both technical and monetary aspect of it. Stay away from price speculation if possible. Some good books to read are "Mastering Bitcoin" by Andreas M. Antonopoulos, or "Bitcoin Standard" by Saifedean Ammous.